Re: [PATCH 00/10] Add Apple M1 support to PASemi i2c driver

On Sun, Sep 26, 2021 at 12:00 PM Sven Peter [off-list ref] wrote:

This series adds support for the I2C controller found on Apple Silicon Macs
which has quite a bit of history:

Apple bought P.A. Semi in 2008 and it looks like a part of its legacy continues
to live on in the M1. This controller has actually been used since at least the
iPhone 4S and hasn't changed much since then.
Essentially, there are only a few differences that matter:

        - The controller no longer is a PCI device
        - Starting at some iPhone an additional bit in one register
          must be set in order to start transmissions.
        - The reference clock and hence the clock dividers are different

In order to add support for a platform device I first replaced PCI-specific
bits and split out the PCI driver to its own file. Then I added support
to make the clock divider configurable and converted the driver to use
managed device resources to make it a bit simpler.

The Apple and PASemi driver will never be compiled in the same kernel
since the Apple one will run on arm64 while the original PASemi driver
will only be useful on powerpc.
I've thus followed the octeon (mips)/thunderx(arm64) approach to do the
split: I created a -core.c file which contains the shared logic and just
compile that one for both the PASemi and the new Apple driver.

This looks all very good to me, I had one very minor comment.

Whole series

Reviewed-by: Arnd Bergmann <arnd@arndb.de>

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